(CNET) — Hurricane Sandy may have passed the Mid-Atlantic region, but its effects are still being felt online.The storm knocked out power and caused severe flooding across the Northeastern United States. New York City power companies pulled the plug on parts of lower Manhattan yesterday, shutting down Web sites without redundant servers. Many of those data centers remained down Tuesday, and power provider Con Edison said power likely won’t be restored to Manhattan for about four days.Several Web sites continue to experience problems, with many taking to Twitter to make announcements. Others have set up special pages to update readers.

Gawker, for one, continued to publish updates on a special site following flooding at its data center. The same was true for Gizmodo, which also set up a live blog on its “Sandy 2012 Emergency Site.”The Associated Press, meanwhile, said its credit-card processing was down due to the hurricane. And of course, some of the city-related sites haven’t been working very well. That includes John F. Kennedy Airport’s page, which has been having trouble loading.All New York airports remain closed in the wake of the hurricane.

The East River overflowed its banks to flood Manhattan’s Upper East Side. First Avenue at 93rd Street looked more like a river than a street last night.

MarketWatch continued to suffer from tech difficulties stemming from the storm, and it most recently said it hoped to return to full functionality soon.

Much of the Northeast continues to be “offline”, as well:

Buzzfeed, meanwhile, posted a short blog yesterday, saying its Manhattan data center was flooded. It was able to get back online because of content delivery network Akamai, which hosts content at servers distributed around the world. The site on Tuesday said via tweet that its site was official back up “after some strokes of genius” by its tech team.The Huffington Post, which set up a special page for updates, was fully back online at about 9 a.m. PT Tuesday.And Livestream.com, which also experienced a major outage, said Tuesday most of the site had recovered. The site tweeted last night that its NYC team was without power because of Sandy.

Massive flooding has damaged several NYC data centers, according to Data Center Knowledge

As for New York’s data centers, Data Center Knowledge is reporting that flooding has crippled two data center buildings in Lower Manhattan, while a third is reportedly without power. Others are likely experiencing outages and running on generators, the site said.Stack Overflow said in a blog post that the company’s data center at 75 Broad Street in Lower Manhattan was running on generator power, but it decided to failover Stack Overflow, Careers, and the rest of the Stack Exchange network to its secondary data center in Oregon yesterday.